[tarice]

This article brings an interesting question to mind -

How will we land humans on Mars without contaminating the planet?

I mean, Mars's atmosphere is mostly CO2, and bacteria are well-known for their ability to survive in harsh conditions. There may not be life on Mars now, but who's to say there won't be after all the astronauts leave...?

[rodly]

Is it wrong to contaminate a space that has no life/use otherwise? I'm not saying Mars as it stands has no use, but if we find no life there, surely spreading life to another planet is "good" right?

[wtetzner]

Well, we might end up thinking there was life on Mars when we're really the ones that brought it. It might screw with the science.

[rodly]

That burden is on us though. Assume we've taken the proper precautions, searched high and low on Mars, and can definitively say no life currently exists in any form on Mars. What does that make Mars?

- A useful resource for studying terrestrial planets - A geologists dream land - A lifeless rock that will likely never host life unless terraformed - A useful resource for spreading life; extending the Human race's finite time in the Universe

I'm not very educated on the ethics of this topic so I'm looking for reasons you would want to leave Mars be indefinitely.

[wtetzner]

I don't disagree with you, I was just trying to come up with a reason we might not want to contaminate it.

If there's no life on Mars, I don't see any obvious ethical problems with introducing life to it.

I mean, I guess maybe if it there was some reason it would be bad for the life forms, versus being bad for Mars.

[bretthoerner]

http://planetaryprotection.nasa.gov/

[sp332]

Well, that's the theory. http://www.msnbc.msn.com/id/45511362/ns/technology_and_scien...

[fghh45sdfhr3]

Did we contaminate the moon? I think if we can can put people on Mars, we'll like that more than not contaminating Mars.

[pc86]

The atmosphere of Mars is over 95% CO2[1] which I imagine could support the propagation of bacteria. The Moon doesn't have much of an atmosphere at all (a trillionth of what the Earth has).[2]

[1] http://en.wikipedia.org/wiki/Atmosphere_of_Mars [2] http://en.wikipedia.org/wiki/Atmosphere_of_the_Moon

[tarice]

A bit of cyanobacteria[1] could theoretically thrive on Mars. All it takes is CO2, sunlight, and water.

[1]http://en.wikipedia.org/wiki/Cyanobacteria

[ars]

They also need nitrogen and trace minerals.

The minerals they could get from soil, but without nitrogen they can't make proteins. The atmosphere of mars is 2.7% nitrogen, but I'm not convinced that that is enough for nitrogen fixation to work.